Integrating Field Experiments with Modeling to Investigate the Dynamics of Alternate Bearing in Citrus

摘要

The management of alternate bearing has become an important issue in fruit production. The potential benefits of applying various alternate bearing control measures on alternate bearing crops can only be realized when yield information on individual trees of particular crops is obtained. This study investigates the dynamics of alternate bearing in citrus via an integrative use of field experiments and numerical simulation models. Fruit yield data on 48 individual trees in an experimental citrus orchard were recorded over a period of 4 consecutive years (from 2002 to 2005). An aerial image was used to measure the canopy size of individual trees. Models were developed based on different combinations of three variables: the time series yield data, thecanopy size and the derived yield density. The models were examined in terms of their potentials to predict fruit yield on individual trees. Results indicated that alternate bearing in citrus behaves more significantly in terms of yield density rather than total fruit yield on individual trees. The model based on canopy size and yield achieved the best prediction performance among the developed models, showing that a simple combination of the canopy size and the total yield for individual trees in one year can provide sufficient information for the yield attainability in the following year. This study demonstrates that the integrative use of field experiments and modeling approach has considerable promise in predicting citrus yield on individual trees.Yield estimates obtained by the proposed method would provide valuable information for planning harvest schedules and developing programs for site- and tree-specific application of variable rate technology (VRT) in citrus management.